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  1. Article ; Online: Eco-friendly synthesis of fused pyrano[2,3-

    Osyanin, Vitaly A / Osipov, Dmitry V / Semenova, Irina A / Korzhenko, Kirill S / Lukashenko, A V / Demidov, Oleg P / Klimochkin, Yuri N

    RSC advances

    2020  Volume 10, Issue 57, Page(s) 34344–34354

    Abstract: Various substituted polycyclic pyrano[2,3- ...

    Abstract Various substituted polycyclic pyrano[2,3-
    Language English
    Publishing date 2020-09-16
    Publishing country England
    Document type Journal Article
    ISSN 2046-2069
    ISSN (online) 2046-2069
    DOI 10.1039/d0ra06450e
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Eco-friendly synthesis of fused pyrano[2,3-b]pyrans via ammonium acetate-mediated formal oxa-[3 + 3]cycloaddition of 4H-chromene-3-carbaldehydes and cyclic 1,3-dicarbonyl compounds

    Osyanin, Vitaly A / Osipov, Dmitry V / Semenova, Irina A / Korzhenko, Kirill S / Lukashenko, A. V / Demidov, Oleg P / Klimochkin, Yuri N

    RSC advances. 2020 Sept. 16, v. 10, no. 57

    2020  

    Abstract: Various substituted polycyclic pyrano[2,3-b]pyrans were synthesized via the condensation of 4H-chromene-3-carbaldehydes and their areno-condensed analogues with hetero- and carbocyclic 1,3-dicarbonyl compounds in acetic acid. Ammonium acetate was used as ...

    Abstract Various substituted polycyclic pyrano[2,3-b]pyrans were synthesized via the condensation of 4H-chromene-3-carbaldehydes and their areno-condensed analogues with hetero- and carbocyclic 1,3-dicarbonyl compounds in acetic acid. Ammonium acetate was used as a green catalyst for the reaction. The process also involves the subsequent Knoevenagel condensation and 6π-electrocyclization of the 1-oxatriene intermediates formed. Fused pyridines were isolated as the products of the conjugated addition of ammonia to 1-oxatriene intermediates while using carbocyclic 1,3-dicarbonyl compounds and increasing the reaction time, indicating the reversibility of the electrocyclization stage. The calculated values of the Gibbs free energies and reaction rate constants for the 1-oxatriene – 2H-pyran equilibrium also testified to the irreversibility of pyrano[2,3-b]pyran formation in the case of using of heterocyclic 1,3-dicarbonyl compounds.
    Keywords Gibbs free energy ; acetic acid ; ammonia ; ammonium ; ammonium acetate ; catalysts ; condensation reactions ; cycloaddition reactions ; pyrans ; pyridines ; synthesis
    Language English
    Dates of publication 2020-0916
    Size p. 34344-34354.
    Publishing place The Royal Society of Chemistry
    Document type Article
    Note NAL-light
    ISSN 2046-2069
    DOI 10.1039/d0ra06450e
    Database NAL-Catalogue (AGRICOLA)

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  3. Article: Catalyst-Free Synthesis of Chromane-Type N,O-Acetals via Intramolecular Addition of Phenols to Enamines

    Osyanin, Vitaly A. / Osipov, Dmitry V. / Melnikova, Irina V. / Korzhenko, Kirill S. / Semenova, Irina A. / Klimochkin, Yuri N.

    Synthesis

    2020  Volume 52, Issue 23, Page(s) 3604–3621

    Abstract: A new strategy to 2-aminochromanes through catalyst-free cascade reaction of 3-trifluoroacetyl-4 H -chromenes and 4 H -chromene-3-carbaldehydes with cyclic secondary amines is presented. The reaction proceeds through subsequent 1,4- and 1,2-additions of ... ...

    Abstract A new strategy to 2-aminochromanes through catalyst-free cascade reaction of 3-trifluoroacetyl-4 H -chromenes and 4 H -chromene-3-carbaldehydes with cyclic secondary amines is presented. The reaction proceeds through subsequent 1,4- and 1,2-additions of amine, bimolecular elimination of trifluoroacetamide or formamide, and 6- exo trig cyclization. The latter stage is a very rare example of addition of phenols to enamines. The obtained semicyclic N,O-acetals were applied as useful precursors for the synthesis of other chromanes.
    Keywords chromanes ; 4 ; -chromenes ; cascade reactions ; enamines ; cyclic secondary amines ; N,O-acetals
    Language English
    Publishing date 2020-07-27
    Publisher © Georg Thieme Verlag
    Publishing place Stuttgart ; New York
    Document type Article
    ZDB-ID 2033062-5
    ISSN 1437-210X ; 0039-7881
    ISSN (online) 1437-210X
    ISSN 0039-7881
    DOI 10.1055/s-0040-1707209
    Database Thieme publisher's database

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